This invention refers in general terms to valves for controlling the level of the liquid in stationary tanks and more particularly concerns to a valve for controlling the level of liquids in stationary tanks such as toilets, humidifiers and the like, which prevents leaks therein.
Normally, the best known valves in this field consist of a system of rocker arm and chain by means of which the movement of a manual lever joined to a cable or the like pulls a plug which obstructs the discharge orifice, causing the tank to empty; a float descends at the same time as the level of the liquid, opening an orifice for admitting liquid which permits the tank to refill as soon as the plug has been replaced and seals the outlet orifice. When the level of the liquid rises in the tank, the float returns to its initial position and by means of the rod to which it is attached it closes the inlet opening for liquid to enter the tank. This system also normally includes a vertical tube connected to the discharge and having its upper open end at a certain level in order to prevent the level of the liquid in the tank from rising higher than this tube which functions as an overflow.
Such systems are subject to an unlimited number of misfunctions; one of the most frequent consists in the plug not sealing hermetically the discharge orifice, either because of some sediment accumulated in the discharge orifice or merely because it was mispositioned through the failure of some guiding device. This causes considerable losses of liquid, which may have serious consequences due to the scarcity of the liquid especially in certain arid zones.
Another frequent misfunction of these systems, particularly in toilet tanks, is that the required quantity for a normal flushing is not obtained with the float at a certain level. The user normally applies an apparent solution to this problem by bending the rod which is connected to the float to allow the level of liquid in the tank to rise to a higher level. This operation weakens the threading or connection of the float with the rod and in reality generally increases number of problems in the system, sometimes causing the level of the water to rise higher than the overflow tube intake, thus producing a waste of the liquid, this time because of the higher level it reaches in the tank.
This last drawback can be summarized by saying that to date no systems have existed allowing an easy adjustment of the level of the liquid contents within the tank; another fundamental drawback of the conventional systems has been that because of the need for a strong hermetic seal at the intake orifice or feed line to the tank, the lever arm or rod connected to the float has has to be of such a length as precludes a compact width dimension for the tank.
To solve the problems above mentioned, which result essentially in a considerable loss of water, extremely sophisticated systems of cylindrical cams or the like have been devised requiring finishing with machine tools which increase production cost, this latter being the principal reason that they have not been able to supplant the traditional systems.